https://stackoverflow.com/a/59004613/6615163
In [1]: import re
In [2]: listA = ['123', '345', '678']
In [3]: listB = ['ABC123', 'CDE455', 'GHK678', 'CGH345']
In [4]: # Mapping b/w number in listB to related index
In [5]: mapping = {re.sub(r'\D+', '', value).strip(): index for index, value in enumerate(listB)}
In [6]: mapping # Print mapping dictionary
Out[6]: {'123': 0, '455': 1, '678': 2, '345': 3}
In [7]: # Find the desired output
In [8]: output = [mapping.get(item) for item in listA]
In [9]: output
Out[9]: [0, 3, 2]
In [10]: